Field of the Invention
The present invention relates to a conductive polymer composition containing a π-conjugated conductive polymer, a coated article using the same, and a patterning process. In particular, the present invention relates to a conductive polymer composition that is suitably used for prevention of electrification of a resist in lithography using ultraviolet light, electron beam, or the like, an article having an antistatic film formed by using the same, and a patterning process using the composition.
Description of the Related Art
Conventionally, in a process of producing a semiconductor device such as IC and LSI, microprocessing by a lithography process using a photoresist has been carried out. This is a method of etching a substrate using as a mask a resist pattern that is obtained by a development treatment using a solvent or the like, the development treatment in which light irradiation induces bridging or a decomposition reaction of a thin film to remarkably change the solubility of the thin film. In recent years, with increased integration of a semiconductor device, high-precision microprocessing using light beam with short wavelength has been required. The development of lithography using electron beam has been advanced as a next generation technique since the electron beam has short-wavelength properties.
The lithography using electron beam has a specific problem of electrification phenomenon (charge-up) during exposure. This is a phenomenon in which in a substrate to be irradiated with electron beam that is covered with an insulating resist film, the resist film is charged with electricity by accumulation of charge on or in the resist film. An orbital of incident electron beam is bent by this electrification, and therefore the precision of drawing is significantly reduced. Accordingly, an antistatic film to be applied on an electron beam resist has been investigated.
However, when the antistatic film is formed on a chemically amplified resist, the shape or the sensitivity of the resist may change. For example, when an acid produced by exposure is neutralized by a component in the antistatic film, an exposed area of the resist in a positive type is not dissolved during development, or an exposed area of the resist in a negative type is partially dissolved during development. Alternatively, by an acid component in the antistatic film, a non-exposed area of the resist in the positive type is partially dissolved during development, or a non-exposed area of the resist in the negative type is not dissolved during development. Since the chemically amplified resist does not have resistance to most organic solvent, an aqueous antistatic agent to be formed on the resist is often used. However, since a surface of the chemically amplified resist is hydrophobic, the aqueous antistatic agent is unlikely to be applied. Therefore, it is necessary to add a surfactant, and the like. However, the addition of the surfactant may also adversely affect the resist, for example, on the surface of which a mixing layer is formed.
In order to reduce such adverse effects on the resist, Patent Document 1 discloses a conductive composition for formation of a resist pattern that contains an acidic group-substituted aniline-based conductive polymer (A) and a solvent (B), wherein the content of acid component with a molecular weight of 500 or less is 0.03% by mass or less.
Patent Document 2 discloses a conductive composition containing a water-soluble conductive polymer (a) having a sulfonic acid group and/or a carboxyl group, a water-soluble polymer (b) having a nitrogen-containing functional group and a terminal hydrophobic group as a polymeric surfactant that is unlikely to adversely affect a resist, and a solvent (c).
Patent Document 3 discloses an antistatic agent containing a water-soluble conductive polymer, a solvent, and a water-soluble polymer having a chemical structure represented by —(N(R′)—CH(R)—C(═O))—.